The disclosure of U.S. Provisional Application No. 61/402,123, filed Aug. 24, 2010, is hereby incorporated herein in its entirety by reference.
It is difficult to chop and pack efficiently agricultural biomass material (like sugarcane billets, straw or grass silage) or forestry biomass (wood chips). If the biomass, as an example cane billets harvested with a sugarcane harvester, is harvested as chopped material (billets of approximately 10 cm), there is a need for many trucks or trailers to follow the forage harvester. However, this creates traffic and soil compaction and valuable juice can be lost on the ground.
The objective of this large-scale chopped biomass harvesting (in bulk) is typically to chop the material, keep the juice (like for sugarcane harvesting), pack it only once in a rectangular bale and transport it with minimum disturbance and maximum density. One known option for packing is to compact the material repeatedly with a horizontal plunger from the top (like packing a cotton module). However, to bale a large bale, e.g., 8 foot by 8 foot, horizontally using such conventional vertical plunger would be difficult to obtain a high crop density. So packing in successive horizontal layers and using gravity force (like packing bunker silos) is believed to be more realistic.
Apparatus configured and operable for packing crop material, and particularly hay, in successive horizontal layers are well known. One known device is disclosed in Luscombe U.S. Pat. No. 3,907,139, issued Sep. 23, 1975, entitled Stack Forming Device. This device utilizes a horizontal compaction roller supported on guide structure supported from cables. In operation, the roller moves end to end along the guide structure through a stack forming chamber, to compact the crop material into the stack. However, the device relies on the weight of the roller and guide structure alone to provide the compacting force. This can limit the density of packing that can be achieve using that device. Also, because the support structure is supported by flexible cables, it can easily tilt and result in an uneven stack. Also, the roller of the Luscombe device is relatively large in diameter, and the edges of the guide structure occupy the peripheral regions of the chamber, such that the periphery of the stack may not be well compacted.
Another known stack forming device is disclosed in Kline et al. U.S. Pat. No. 3,922,838, issued Dec. 2, 1975, and entitled Machine For Forming A Compact Stack Of Crop Material. This device utilizes a shaped packing roll supported on a carriage frame within a stack forming chamber and movable along a curved path end to end within the chamber for forming a crowned stack. The packing roll is supported by walls of the chamber, and cylinders are provided for raising and lowering the walls and driving the packing roll against the stack for better compaction. The Kline et al. device also includes a baffle member in connection with the packing roll operable for deflecting an incoming flow of crop material downwardly onto the stack being formed, which is described as being and movable from time to time for distributing the crop material onto the stack. However, the Kline et al. device forms a crowned stack which is larger in the middle and no manner for distributing the crop material to form a level stack is disclosed.
Therefore, what is sought is apparatus for forming a unitary bale of agricultural or forestry biomass, capable of forming a bale of substantially uniform density and having a level top, which overcomes one or more of the shortcomings and limitations set forth above.